<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
    <style>
      .circle {
        width: 100px;
        height: 100px;
        border-radius: 50%;
        background-color: tomato;
     
        animation: scaleUp 2s ease 0s infinite;
      }
      @keyframes scaleUp {
        from {
                transform: scale(1);
            }
            to {
                transform: scale(0.5);
            }
      }
    </style>
  </head>
  <body>
    <div class="circle"></div>
  </body>
</html>
